Monthly Archives: June 2013

The HDMI Switcher box is a good solution for creating additional HDMI input ports. For older HDTVs or other displays with one HDMI port, a HDMI Switcher box can be used to share a single port. It is like a selector switch from the old days that allowed the sharing of a single computer monitor with multiple computers. Obviously, there is a lot more complexity to a HDMI switch box. For example, almost all of them have remote control that allows the user to control them in the same way a TV is controlled.

So, what would be a typical scenario where a HDMI Switcher Box is used. Lets say you have a HD video camera, PSP video game and a Blue Ray player. Your HDTV only has one HDMI port. Instead of spending thousands of dollars on a newer HDTV with many more HDMI ports, you can simply purchase a 3-to-1 HDMI switch box for much less and would work perfectly for this situation. The hook up is simple, you would need to purchase a HDMI Cable for each source (i.e., the PSP game, Blue Ray Player, etc …) that connects to one of the HDMI inputs on the Switcher box and a HDMI Cable to connect the output of the switch box to the HDMI input port on the HDTV.

Here is an example of a pretty good HDMI switcher box from Amazon:

Like HDMI itself, most of the HDMI switch boxes on the market are kind of smart – meaning they have some level of automation. It will detect which source is the last one to be powered on and give that one priority to the HDTV display. There is usually some type of LED indicator to show which source is selected at any one time. Also, the user has the ability to override the automatic behavior with the remote control. They can manually select which source to show on the HDTV.

As a general matter, most HDMI Switcher boxes have similar features and construction. There are too many manufacturers to mention and I am not in the practice of pushing one brand over the next. But, there are certainly functions and features you can compare to make an informed buying decision. In terms of HDMI Cable versions, there is pretty good compatibility between the latest standard and high-speed HDMI Cables and most of the switches on the market. The thing to be mindful of is that there are a few HDMI features that are Not supported yet: the Ethernet channel and Audio Return. Some of the lower end devices do not come with IR receivers or remote. That might be a reason to stay away from those types. Another thing to look out for is whether the HDMI switch box comes with its own power supply are whether it is powered from the HDMI Cable. My suggestion is to stay away from devices that don’t have an independent power source. They tend to not work as well.

Here are a couple of issues that you might run into and how to debug them:

In the following section “Tech Talk”, I will get a little bit more technical about the HDMI Switch Box and what is inside it.

##################### TECH TALK #######################

Inside the HDMI switch box, basically, you have what is know as a MULTIPLEXER. This component is used in the Electronic Engineering world for selecting between different signal sources. I can go deep into the details of Boolean equations, logic diagram and truth tables to explain the digital behavior of a MULTIPLEXER but, I will save that for another time. Instead, I will use a highway analogy to convey the point.

Imagine you have a three (3) lane highway that merges into one (1). The merging process is controlled by traffic lights. Therefore, at the point of merger, the incoming lane that has a green light is allowed to merge into the single exiting lane. If one incoming lane has the green light then the other two incoming lanes will see a RED light. The lights can be controlled automatically by sensors in the lanes or they can be controlled manually by a traffic cop. That is the essence of how a Multiplexer and the HDMI Switcher box works.

Also, some of these devices have repeater circuitry to help restore and signal loss that might have occurred as a result of multiplexing the digital signals.